Dehydrogenation reactions are endothermic reactions and require the input of heat to carry the reaction. At higher temperatures, higher conversion can be achieved. Thus, higher temperatures are often desirable. At higher temperatures, however, coking of the catalyst increases. In the dehydrogenation of hydrocarbons, such as the dehydrogenation of propane to propylene, platinum is generally used for the active catalyst component for steam-based dehydrogenation reactions. In such reactions, the primary cause of catalyst deactivation is due to the buildup of coke on the catalyst and catalyst support surface. The buildup of coke results in thermal decomposition of the alkane/alkene and eventually inhibits the dehydrogenation reaction at the platinum surface. Catalysts that have accumulated too much coke may become unusable or must undergo a regeneration process.
Catalyst supports with a high surface area are typically desired because they allow a higher dispersion of platinum on the support surface. A high surface area generally corresponds to smaller pore diameters of the catalyst support. If the surface area is too high the pore diameters may be so small that they are prone to plugging from coke. This is because the smaller diameter pores are restricted so that oxygen used for regeneration cannot diffuse and reach the coke in the depths of the pores during the regeneration cycle. This ultimately leads to blocked pores containing platinum that is thus not accessible for the dehydrogenation reaction.
The present invention is therefore directed to a method of providing a dehydrogenation catalyst support and catalyst that overcomes these shortcomings.